How do you identify mystery fabric with no content label?

Picked up about 4 yards of fabric at an estate sale last weekend for $5. No selvage info, no bolt, just folded in a bag. It has a really nice drape, almost like a crepe but smoother. Slightly textured on one side. Doesnt wrinkle much when I scrunch it. Burns slowly with a chemical smell so Im guessing some kind of poly blend but it honestly feels nicer than that. What tests do you guys use to figure out fiber content when theres no label? Ive heard about the burn test but are there other tricks?